基于改进锁频环的并网变流器惯性增强控制方法

李星; 翟保豫; 梁树超; 唐伟瀚; 陈章勇; 陈勇

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电力建设 ›› 0

基于改进锁频环的并网变流器惯性增强控制方法

李星^1,2, 翟保豫², 梁树超², 唐伟瀚¹, 陈章勇¹, 陈勇¹

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Inertia Enhancement Control Strategy of Grid Connected Converter Based on Frequency Lock Loop

LI Xing^1,2, ZHAI Baoyu², LIANG Shuchao², TANG Weihan¹, CHEN Zhangyong¹, CHEN Yong¹

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摘要

【目的】由于电力电子变流器的并网特性,电力系统在新能源发电占比不断提高的背景下,整体惯性显著降低。为了增强电力系统的频率稳定性和抗扰动能力,要求并网变流器主动提供惯性支撑。【方法】在功率分配控制策略基础上,深入分析了基于常规锁相环（phase locked loop, PLL）控制结构的零极点分布及其在并网控制中的稳定性下降问题,提出了一种适用于并网变流器的基于改进锁频环（frequency locked loop, FLL）控制结构的惯性增强控制结构,将频率导数信号与参考有功功率成比例结合,以解决功率振荡问题。并且,一种改进的模型预测控制被用于代替传统电流内环,以改善动态性能。【结果】通过频率阶跃响应的对比,展示了在弱电网条件下基于改进锁频环控制结构在并网变流器频率稳定性方面的优势。给出了基于改进锁频环架构的有功环控制策略,阐述了其惯量增强的原理,并对惯性参数进行了调优设计。【结论】该方法避免了因微分操作引入的高频噪声和锁相环导致的不稳定问题,显著改善了系统的频率响应特性,实现了系统惯性增强的控制目标。最后,通过硬件在环（hardware in loop, HIL）实验验证了所提策略的有效性。

Abstract

[Objective] With the increasing penetration of renewable energy sources, the overall inertia of power systems has significantly declined due to the gradual replacement of traditional rotating machines by power electronic converters. This reduction in inertia poses serious challenges to frequency stability and system disturbance rejection. To address this issue, grid-connected converters are required to actively provide synthetic inertia support. [Methods] Based on a power-sharing control strategy, this paper analyzes the pole-zero distribution characteristics of conventional Phase-Locked Loop (PLL)-based control structures and highlights the associated stability degradation under weak grid conditions. To overcome these limitations, an inertia enhancement control scheme based on an improved Frequency-Locked Loop (FLL) structure is proposed. By proportionally integrating the frequency derivative signal with the reference active power, the proposed method effectively mitigates power oscillations and enhances the inertial response of the converter. Furthermore, a modified Model Predictive Control (MPC) strategy is employed to replace the conventional inner current loop, significantly improving the system's transient performance. [Results] Comparative studies of frequency step responses demonstrate the superiority of the proposed FLL-based structure in maintaining frequency stability under weak grid conditions. The active power control strategy under the improved FLL framework is detailed, along with the principle of inertia emulation and the tuning of associated parameters. [Conclusions] The proposed method avoids high-frequency noise issues caused by direct differentiation of frequency signals and eliminates the stability problems typically introduced by PLL. As a result, the frequency response of the system is substantially improved, and the goal of synthetic inertia enhancement is achieved. The effectiveness of the proposed control strategy is further validated through Hardware-in-the-Loop (HIL) simulation experiments.

导出引用

李星, 翟保豫, 梁树超, 唐伟瀚, 陈章勇, 陈勇. 基于改进锁频环的并网变流器惯性增强控制方法[J]. 电力建设. 0

LI Xing, ZHAI Baoyu, LIANG Shuchao, TANG Weihan, CHEN Zhangyong, CHEN Yong. Inertia Enhancement Control Strategy of Grid Connected Converter Based on Frequency Lock Loop[J]. Electric Power Construction. 0

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